The Nikon AF-S Nikkor 400mm F2.8G ED VR II is the latest iteration in a series of fast-aperture extreme telephoto lenses from Nikon going back several decades. A favorite of sports and wildlife photographers, 400mm becomes an effective 600mm on Nikon's DX (APS-C) format-DSLRs, and on full-frame, 400mm is an excellent choice when shooting 'from the touchline'. Optical construction comprises 14 elements in 11 groups, including three ED (extra low-dispersion) glass elements and Nano Crystal Coating. As we'd expect from a professional telephoto, this lens is also weather-sealed.